The neighborhood watch volunteer who got worldwide attention and threats for fatally shooting an unarmed teen is living as a recluse, can go outside only in disguise and is running out of money for his defense, his attorney says.

The fund that George Zimmerman created online after his arrest in April on charges that he killed Trayvon Martin has fallen from $250,000 to $70,000, lawyer Mark O'Mara told USA TODAY.

The donations paid $100,000 for Zimmerman's bond, about $50,000 for security guards for him and his wife, Shelly, and about $30,000 for rent, utilities and other living expenses, O'Mara said.

Some of the balance has been designated for other expenses, and what is left probably won't cover experts and other costs of the case, the lawyer said. O'Mara said he hasn't been paid.

Zimmerman, 28, is charged with second-degree murder for shooting Trayvon, 17, on Feb. 26 after the two got into a fight in a gated complex of townhouses in Sanford, Fla.

Zimmerman says he was in fear for his life as Trayvon slammed his head into the concrete. Prosecutors say he provoked the encounter by following Trayvon and confronting him only because he was a black teen in a hoodie.

O'Mara said Zimmerman and his wife can't work because of the attention they attract and rely on family or friends to bring them groceries.

Zimmerman moved out of his own house and into one in an undisclosed location, still in Seminole County. He last left the house Thursday, O'Mara said. Before that, he had not been outside in three weeks. O'Mara said his office receives a threat or two every week.

"It is scary to be George Zimmerman," he said. "You can't be out in public, so how do you work?" Zimmerman had been working for a mortgage risk-management firm.

Benjamin Crump, the attorney for Trayvon's family, noted pointedly that Zimmerman is alive and free. He killed an unarmed person and yet, Crump said, he was released on bond twice.

Zimmerman was initially released on $150,000 bond, but Circuit Judge Kenneth Lester later set bond at $1 million after finding that he had lied about how much money he had.

On one point Crump and O'Mara agree: This is not a "stand-your-ground" case.

Under Florida's "stand-your-ground" law, a person has no duty to retreat in the face of harm and can use lethal force. That doesn't apply because Zimmerman could not retreat when he was on the ground fending off blows, O'Mara said.

O'Mara said he will try to have the case tossed out. If a judge determines in a pretrial hearing that Zimmerman acted in fear for his life, the charges are dismissed.